So here’s the situation, there’s an outlet in a concrete floor and someone wants a new wood floor to go over the top and it will need 5/8″ plywood attached to the floor and oak over that. The question is how to cut out the plywood so that the hole matches exactly. The process is simple it you have a few tools. First measure where the hole is in the room so you can find it after the plywood is covering it. Get the ply attached to the floor and drill a hole into the electrical box location.
Use your handy router with a flush cut bit to buzz out the opening.
Makes a nice clean hole it just requires that the wires are pushed down beforehand so they don’t get into trouble.